Preformed zigzag spring



March 10, 1953 N. WOLOFSKl 2,631,029

PREFORMED ZIGZAG SPRING Filed March 24, 1948 2 SHEETS--SIIEET l Z9 INVENTOR.

Z/ 4 33- if" I III March 10, 1953 N. WOLOFSKI 2,631,029

PREFORMED ZIGZAG SPRING Filed March 24, 1948 2 SHEETS-SHEET 2 IN V EN TOR. A/Z c%a/4$ f7}; BY

Patented Mar. 10, 1953 UNITED STATES PATENT OFFICE PREFORMED ZIGZAG SPRING Nicholas. w lofsktnetr it, lllicho assignor o. Th Murray Corporation of America,1D,etroit', Mich a corporation of Delaware Application March. 8, Serial No. 16,671

4" Claims. (01; 2679-1) This invention. relates to. springs, and particularly to a flat spring strip having a central load supporting portion set on, an arc of predetermined radius with the. end, portions formed relative thereto in such manner that when extended outwardly from each other and secured to a frame the central load supporting portion is disposed on apredeterminedarc ofv larger radius.

In the patent to KademReissue 21,263, a spring strip is illustrated made of wire bent back and forth in zigzag formation. to. provide adjacent oppositely presenting loops which are set on an are relative to each other so that the strip will assume, when unsupported, a. circle or a portion thereof of predetermined radius. When the ends were extended. and. secured to a frame, resistance Was provided by the set against. downward deflection of the spring thereby supporting a predetermined load and returning to initial position when the load was removed. Such spring strips were employedas main load supporting elements or supports for coil springs upon which padding and upholstery were thereafter provided, when soft edges were desired. at the sprung ends, coil or jack springs were utilized for supporting the ends, or springelements were applied to the top of the spring strips which extended above the ends to provide a soft; edge.

The present invention pertains to the formation of the end portions of spring strips which,

when secured to the frame, resiliently support the end of the central load supporting portion and provide a desired crown, thereto. In other words, the central load supporting portion of the spring is set on an arcof small radius and when the end portions are extended, and secured to, the frame, the radius of the are is substantially increased so that the'load supporting portion assumes a flat arc resulting in the cushion having a proper crown when trimmed.

Accordingly, the main objects of the invention are: to provide a spring strip having the central load supporting portion set upon an arc of predetermined radius, with the end portions reversely bent within the arcuate portion and so formed that when drawn outwardly and secured to a frame, the load supporting portion assumes a desired arc of substantially increased radius; to form a spring strip of a central arched portion and end portions of v shape extending within the arched portion and presenting outwardly therefrom and related in such manner to the arched portion that when the ends are anchored to provide a resilient support therefor, the arch assumes a desired crown for the resulting cushion structure; and, in general, to provide a spring strip having ends, which resiliently support. the load supporting portion thereof which is simple in construction. and economical of manufacture.

Other objects and features; of novelty, of the invention will be specifically pointed out or will become, apparent when. referring, for a better understandi g of the invention, to. the following description 'tal'sen'v in conjunction with the accompanyin drawings, wherein Figure 1 is. a view in elevation. of a spring embodying features of the present, invention, shown with theends unsecured Fig. 2 is a view of structure illustrated in Fig. 1, when the ends are secured to a frame;

Fig. 3 is a broken plan view of the illustrated in Fig. l; r

Fig. 4 is; an enlargedperspective. view of a spring end secured to the frame as illustrated in Fig. 2;

Fig. 5 is a view of structure similar to that illustrated in Fig. 1; showing a further formv of the invention with the ends unsecured; and

structure Fig. 6 is a view of, the structure illustrated in Fig. 5, when, the ends; are; secured to a. frame.

Referring to-Figs, 1L andg2, a spring l0 is illustrated. made, from a wire. l.l bent baokand forth n z za f mation. pro id n opp sit y d e ed alternate loops I2; and I with a central, load supportin p t l dispo d n an a c of. predetermined radius. The; end ii of the load sup,- porting portion to be disposed at the rear of the seating, cushion, is bent at to inwardly. to be directed on a reverse curve toward the under surface of the load supporting portion M. The end convolution I1 is bent relative. to the section it so as to engage the top surface. Of. a rear member [9 of the frame when anchored. thereto by suitable clips 2|, as illustrated in Fig. 2. The front end 22 of the load supporting portion 14 s e t at. 2.3; and. urther bent at? 24. to, have, a b t n ia ly traight por ion. 25.- extend into engagement with the under surface of the load supporting portion It. The end of the portion 25 is bent at 26 and further bent at 21 and extended to provide a substantially straight portion 28. The end 29 of the endmost loop of the extending portion 28 is secured by a suitable clip 2| to the frame member 3| at the front of the frame. The end portions 1! and 29 of the spring strip have an offset at 32 to prevent the end portion from moving outwardly of the eye in the clip when secured therein.

By having the end portions l8 and 25 formed as illustrated in Fig. 1, the stress required to draw the spring ends 29 and H outwardly in engagement with the frame members l9 and 3| changes the arc of the spring supporting portion Hi to provide a desirable crown to the seat. The end portions 18 and 25 produce a desired depth to the resulting seat and resiliency to the support for the forward and rear ends of the load supporting portion M of the spring strip. With such an arrangement, the inherent tendency in the spring strip to move the ends inwardly has been substantially reduced so that the heavy bracing, heretofore required to prevent the frame members such as l9 and 31 from being drawn inwardly toward each other when a plurality of the spring strips were assembled thereon, is substantially eliminated. By predetermining the are upon which the load supporting portion 14 is set, relative to the angularity of the end portions 25 and 18, a desirable resiliency to the load supporting portion and to its end support may be obtained which may similate and improve the spring effects of cushions of various heights made from coil springs.

Referring to Figs. and 6, a similar spring strip is illustrated mounted on a back cushion frame. It is to be understood, however, that either spring strip may be employed alone or in combination in aseat or back cushion. In the arrangement illustrated in Figs. 5 and 6, a load supporting portion 34 is set upon a predetermined are, having one end 35 reversely bent to provide a V-shaped supporting portion 36 disposed against the under surface of the seating portion. The opposite end of the portion 34 is bent at one end of a loop l2 at 3'1 and further bent at the opposite end of the loop at 38 to provide a V-shaped portion 39 which is folded against the under surface of the load supporting portion 34 and presenting outwardly therefrom. The ends 4i and 42 of the V-shaped portions 39 and 35, respectively, are secured by clips 2| to bottom and top rail elements 43 and 44, respectively, of a back supporting frame. When the ends are secured by the clips to the rail elements, the V-shaped supporting portions of the strips 39 and 36, respectively, provide a resilient support for the ends 31 and 35 of the load supporting portion 34 which is disposed upon an arc of large radius. In this arrangement, the V-shaped elements 36 and 39 are so disposed that when the ends are secured to the rail elements, the tension due to the inherent set in the load supporting portion 34 on the small arc resists the movement of the spring ends into engagement with the rail elements so that the load supporting portion assumes the desired crown which in this instance is almost flat when the elements 36 and 39 are anchored to resiliently support the ends thereof.

The spring units herein described, when applied to seating structures, are illustrated, described and claimed in applicants copending application, Serial No. 55,633, filed October 20, 1948, and assigned to the assignee of the present invention. It will be noted therein that a series of the spring units are secured to a frame in adjacent relation to each other to provide a desired contour for the resulting cushion produced when padding and trim material are secured in the conventional manner over the spring assembly.

What is claimed is:

1. A spring strip in the free unattached state having between the ends thereof a load supporting portion set upon an arc of predetermined radius, and end portions abruptly bent from the load supporting portion and extending substantially within the area of the arc of the load supporting portion, said abrupt bends forming a sharp apex.

2. A spring made of wire bent back and forth in zig-zag formation to provide adjacent oppositely presenting loops, said spring in its free state having a portion between the ends thereof set upon an arc of predetermined radius and having an end portion abruptly bent in the shape of a V with the apex of the V disposed within the area encompassed by the arcuate load supporting portion.

3. A spring element made of wire bent back and forth to provide adjacent oppositely presenting U-shaped loops, said spring in its free state having a portion between the ends disposed on an arc ofpredetermined radius, the end portions being of V formation and bent relative to the arcuate load supporting portion so as to have the apex of the V formation disposed within the area of the arcuate portion defined by a chord extending across the ends thereof.

4. A spring strip made of wire bent back and forth to provide adjacent oppositely presenting loops, said spring in its free state having a central load sup-porting portion disposed on an arc of predetermined radius, and a V-shaped portion at one end so positioned within the arcuate load supporting portion as to face toward the center from which the arc was struck.

NICHOLAS WOLOFSKI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,133,611 Freund Oct. 18, 1938 2,251,049 Haberstump July 29, 1941 2,407,933 Neely Sept. 17, 1946 2,440,001 Blumensaadt Apr. 20, 1948 2,568,829 Scott et al. Sept. 25, 1951 FOREIGN PATENTS Number Country Date 498,160 Germany Nov. 12, 1931 

